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Vulnerability · Published Oct 28, 2026 · Assigned by Linux

CVE-2026-99110smb: client: fix heap overflow in cifs_do_set_acl()

High 7.0

In plain English

A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 3% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.0High
Exploit odds (30 days)0.1%top 97.0% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix heap overflow in cifs_do_set_acl() cifs_set_acl() validates ACL size using posix_acl_xattr_size(): 4 + (count * 8) // 4-byte header + 8 bytes per ACE cifs_do_set_acl() then calls posix_acl_to_cifs() to write the CIFS wire format into the same buffer: 6 + (count * 10) // 6-byte header + 10 bytes per ACE An ACL that passes the xattr-based check in cifs_set_acl() can overflow the heap when posix_acl_to_cifs() writes the larger CIFS format. Validate the CIFS format size against the remaining buffer space and USHRT_MAX before converting--data_count is __u16, so sizes above USHRT_MAX truncate the on-wire packet length, causing the server to apply a partial ACL. Replace MaxDataCount = 1000 with min(CIFSMaxBufSize, USHRT_MAX).

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13linux6.12.115-2DEBIAN-CVE-2026-99110
Debian:14linux7.2.13-1DEBIAN-CVE-2026-99110
Ubuntu:24.04:LTSlinuxno fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinuxno fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-awsno fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinux-awsno fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-aws-6.8no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-aws-7.0no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-azure-6.8no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-azure-7.0no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-azure-fde-6.8no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-azure-fde-7.0no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-gcp-6.8no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-gcp-7.0no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-hwe-6.8no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-hwe-7.0no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-ibm-6.8no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-lowlatencyno fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.8no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-nvidia-6.8no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-nvidia-7.0no fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinux-nvidia-bosno fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-nvidia-lowlatencyno fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-nvidia-tegrano fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinux-oem-7.0no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-oracle-6.8no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-oracle-7.0no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-99110
Ubuntu:26.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-riscv-6.8no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-riscv-7.0no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-99110
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-vmwareno fix listedUBUNTU-CVE-2026-99110
Ubuntu:24.04:LTSlinux-xilinxno fix listedUBUNTU-CVE-2026-99110

Affected products (as reported)

VendorProductVersions
Linux Linux dc1af4c4b4721abfa07b351063825acc7e69cc66 – before 68652afb9b9adf70125971abee9b95341e042249dc1af4c4b4721abfa07b351063825acc7e69cc66 – before 9312a00215602ba028495ef3fa00fb84af0478e0dc1af4c4b4721abfa07b351063825acc7e69cc66 – before d96f3365ce61c5f39602955af43c8174548dee98dc1af4c4b4721abfa07b351063825acc7e69cc66 – before 596b4062e6c75bdd85a7f2b7f2087a872dc420acdc1af4c4b4721abfa07b351063825acc7e69cc66 – before 1dac61e2c29d1a71784604b48cf3b1234a65ec29
Linux Linux 6.2

References